How Do You Calculate the Charges on Two Repelling Particles?

[fallen186]

Homework Statement

Two point particles separated by 0.4 m carry a total charge of 185 µC.
(a) If the two particles repel each other with a force of 80 N, what are the charges on each of the two particles?

Homework Equations

F = k* (q1*q2)/(r^2)

The Attempt at a Solution

I tried using altering the formula so it would be 80 = (185-x)*(x) /(.4^2). I tried putting this in my calculator in which y1 = (185-x)*(x)/(.4^2), y2= 80 yet it tells me it intersects at x = 184.9. Um what did i do wrong? I would appreciate the help :).

 

[AEM]

Two quick questions: What happened to k? and Shouldn't you do something with that micro coulombs that follows the 185?